1. Field of the Invention
The present invention relates to an endoscope in which a distal end portion is attached at a position that is further on a distal end side than a bending portion that has a tubular structure.
2. Description of the Related Art
In some endoscopes, a bending portion that is configured so as to be capable of bending is provided in an insertion portion. In an endoscope capable of bending in this manner, a rigid distal end portion that has an observation portion for observing an observation site (observation object) is disposed at a position that is further on a distal end side than the bending portion.
Conventionally, a screw or the like has been used to connect the distal end portion and the bending portion in such endoscopes.
For example, in FIG. 1 and paragraph [0014] of Japanese Patent Application Laid-Open Publication No. 2003-325527, it is described that a joint ring (21) at a distalmost end that is included in a bending portion (2) is fitted in the vicinity of a rear end of a distal end portion body (3) and is coupled thereto by means of a small screw (22).
Further, in FIG. 6 and paragraph [0013] of Japanese Patent Application Laid-Open Publication No. 2002-034895, it is described that a portion close to the rear of a distal end portion body (5) is fitted into a portion close to the tip of a joint ring (31a) located at a distalmost end of a bending portion (3) and is fixed thereto with a screw.
In addition, in FIGS. 1 and 3 and paragraph [0014] of Japanese Patent Application Laid-Open Publication No. 10-192219, it is described that a distal end portion body (31) and a bending portion (32) are connected by screwing a joint ring (33) that is at a distalmost end to a pair of screw pieces (37) made of metal that are embedded in a concave portion of the distal end portion body (31) and in which a female screw thread is threaded.
In this connection, for example, in an endoscope that is compatible with high frequency treatment or the like, in order to form a structure that electrically insulates an endoscope distal end portion from a living organism, in some cases a resin is used as a material for forming the distal end portion. When connecting a bending portion and a distal end portion that is made of resin, the bending portion and the distal end portion made of resin are fixed together by means of an adhesive.